U.S. patent number 4,199,545 [Application Number 05/792,858] was granted by the patent office on 1980-04-22 for fluid-wall reactor for high temperature chemical reaction processes.
This patent grant is currently assigned to Thagard Technology Company. Invention is credited to Edwin Matovich.
United States Patent |
4,199,545 |
Matovich |
April 22, 1980 |
**Please see images for:
( Certificate of Correction ) ** |
Fluid-wall reactor for high temperature chemical reaction
processes
Abstract
A fluid-wall reactor for high temperature chemical reactions is
described, the reactor comprising (A) a porous reactor tube, at
least a portion of the interior of which defines a reaction zone,
the tube being made of a fabric of a fibrous refractory material;
(B) a pressure vessel enclosing the reactor tube to define an inert
fluid plenum, the pressure vessel having at least one inlet for
admitting the inert fluid which is directed under pressure through
the porous tube wall to provide a protective blanket for the inside
surface of the reactor tube; (C) means for introducing at least one
reactant into the reaction zone, the reactants being directed in a
predetermined path axially of the reactor tube and being confined
by the protective blanket substantially centrally within the
reaction zone; (D) means disposed within the plenum for heating the
reactor tube to the temperature level at which it emits sufficient
radiant energy to initiate and sustain the desired chemical
reaction, the radiant energy being directed into the reaction zone
to coincide with at least a portion of the path of the reactants;
and (E) a heat shield disposed within the pressure vessel,
substantially enclosing the heating means and the reaction zone to
define a black body cavity, the heat shield reflecting radiant
energy toward the reaction zone. The fluid-wall reactor of the
invention may be used in virtually any high temperature chemical
reaction, many of which reactions have been previously regarded as
impractical or only theoretically possible. Among the reactions
which may be carried out in the fluid-wall reactor of the invention
as the dissociation of hydrocarbons and hydrocarbonaceous
materials, such as coal and various petroleum fractions, into
hydrogen and carbon black; the steam reforming of coal, petroleum
fractions, oil shale, tar sands, lignite, and any carbonaceous or
hydrocarbonaceous feedstock into synthesis gas mixtures; the
partial dissociation of hydrocarbons and hydrocarbonaceous
materials into lower molecular weight compounds; the partial
pyrolysis of saturated hydrocarbons into unsaturated hydrocarbons,
such as ethylene, propylene and acetylene; the conversion of
organic waste materials, such as sewage sludge, into a fuel gas;
the complete or partial desulfurization of sulfur-containing
hydrocarbonaceous feedstocks; and the reduction of mineral ores
with hydrogen, carbon, synthesis gas, or other reducing agent.
Inventors: |
Matovich; Edwin (Brea, CA) |
Assignee: |
Thagard Technology Company
(Irvine, CA)
|
Family
ID: |
27085177 |
Appl.
No.: |
05/792,858 |
Filed: |
May 2, 1977 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
606222 |
Aug 20, 1975 |
|
|
|
|
271560 |
Jul 13, 1972 |
3933434 |
|
|
|
Current U.S.
Class: |
422/112; 373/113;
422/129; 422/186.04; 422/199; 422/241; 219/549; 422/109; 422/150;
422/198; 422/240 |
Current CPC
Class: |
C22B
5/02 (20130101); C10J 3/76 (20130101); C21B
13/00 (20130101); B01J 12/005 (20130101); C09C
1/48 (20130101); C21B 13/04 (20130101); C01B
3/342 (20130101); C01B 32/70 (20170801); C10J
3/78 (20130101); C10G 32/02 (20130101); C10G
32/04 (20130101); C10J 3/74 (20130101); C10J
3/506 (20130101); C10J 3/723 (20130101); C10J
3/466 (20130101); C09K 3/1436 (20130101); C01B
32/90 (20170801); C10G 15/08 (20130101); Y02P
10/212 (20151101); C10J 2300/0946 (20130101); C10J
2300/1269 (20130101); C10J 2300/1246 (20130101); C10J
2300/093 (20130101); Y02P 10/136 (20151101); Y02P
10/134 (20151101); Y02P 10/20 (20151101); C10J
2300/0976 (20130101); C01P 2006/60 (20130101); C10J
2300/0959 (20130101); C10J 2300/0906 (20130101); C01P
2004/20 (20130101); C01P 2004/32 (20130101) |
Current International
Class: |
C09C
1/44 (20060101); C10J 3/74 (20060101); C22B
5/02 (20060101); C10J 3/00 (20060101); C22B
5/00 (20060101); C10G 32/00 (20060101); C10G
32/02 (20060101); C21B 13/04 (20060101); C10G
15/00 (20060101); C10G 15/08 (20060101); C10G
32/04 (20060101); C21B 13/00 (20060101); B01J
12/00 (20060101); C01B 3/00 (20060101); C01B
31/00 (20060101); C01B 3/34 (20060101); C01B
31/26 (20060101); C01B 31/30 (20060101); C01B
31/08 (20060101); C09C 1/48 (20060101); C09K
3/14 (20060101); B01J 001/00 () |
Field of
Search: |
;23/252R,277,284
;423/447.1,447.2 ;250/527 ;13/31,32,20 ;219/405
;422/240,242,199,150,129,112 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Turk; Arnold
Attorney, Agent or Firm: Pennie & Edmonds
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation of application Ser. No. 606,222,
filed Aug. 20, 1975 and now abandoned, which in turn was a
continuation-in-part of application Ser. No. 271,560, filed July
13, 1972 and now U.S. Pat. No. 3,933,434.
Claims
I claim:
1. In a high temperature reactor wherein substantially all of the
heat is supplied by radiation coupling, comprising
(a) a reactor tube having an inlet end and an outlet end, the
interior of the tube defining a reactor chamber, the reactor tube
being made of a porous refractory material capable of emitting
sufficient radiant energy to raise the temperature of reactants
within the reactor tube to a level required to initiate and sustain
the desired chemical reaction, the pores of the refractory material
being of such diameter as to permit a uniform flow of sufficient
inert fluid which is substantially transparent to radiant energy
through the tube wall to constitute a protective blanket for the
radially inward surface of the reactor tube;
(b) a fluid-tight, tubular pressure vessel enclosing the reactor
tube to define an inert fluid plenum between the reactor tube and
the pressure vessel, the inlet and outlet ends of the reactor tube
being sealed from the plenum; the pressure vessel having an inlet
for admitting the inert fluid which is directed under pressure into
the plenum and through the porous tube wall into the reactor
chamber;
(c) means for introducing at least one reactant into the reactor
chamber through the inlet end of the reactor tube, the reactants
being directed in a predetermined path axially of the reactor tube
and being confined by the protective blanket substantially
centrally within the reactor chamber and out of contact with the
inner wall of the reactor tube;
(d) electrical means disposed within the plenum and spaced radially
outwardly of the reactor tube for heating the reactor tube to the
temperature level at which it emits sufficient radiant energy to
initiate and sustain the desired chemical reaction, the radiant
energy being directed centrally therewithin substantially
coincident with at least a portion of the path of the reactants;
and
(e) a circumferential heat shield disposed within the pressure
vessel and radially outwardly of the heating means, the heat shield
reflecting radiant energy toward the reactor tube;
the improvement in combination therewith comprising:
(i) a reactor-tube assembly, including
(i.1) the reactor tube of paragraph (a) of the preamble, the
reactor tube being made of a porous fabric of a fibrous, refractory
material;
(i.2) a first support ring having an opening passing therethrough,
the first support ring being secured to the inlet end of the
reactor tube with the opening of the support ring generally coaxial
with the opening in the inlet end of the reactor tube so that the
opening of the first support ring communicates with the interior of
the reactor tube through the inlet-end opening; and
(i.3) a second support ring having an opening passing therethrough,
the second support ring being secured to the outlet end of the
reactor tube with the opening of the support ring generally coaxial
with the opening in the outlet end of the reactor tube so that the
opening of the second support ring communicates with the interior
of the reactor tube through the outlet-end opening; and
(ii) means for attaching the first and the second support rings to
the pressure vessel to position the reactor tube within the
pressure vessel.
2. The high temperature reactor according to claim 1 in which the
fibrous fabric of the reactor tube is stiffened to as to be capable
of withstanding without collapsing a fluid pressure differential
between the radially outward surface and the radially inward
surface of the reactor tube resulting from the flow of inert fluid
through the tube wall.
3. A fluid-wall reactor according to claim 1, in which the fibrous
refractory material is graphite or carbon.
4. A fuid-wall reactor according to claim 1, further including
means for applying an axial tensile force to the reactor tube.
5. A fluid-wall reactor according to claim 1, further including
means for cooling the pressure vessel.
6. A fluid-wall reactor according to claim 1, in which a portion of
the interior of the reaction tube between the inlet end of the tube
and the reaction zone defines a prereaction zone into which the
inert fluid is directed to form a protective blanket which assists
in confining the reactants substantially centrally within the
reaction zone and out of contact with the inner wall of the reactor
tube.
7. A fluid-wall according to claim 1, in which means for
introducing a solid reactant into the reaction zone of the reactor
tube includes a helical feed screw rotatably mounted within an
elongated tubular housing, drive means for rotating the feed screw,
a hopper for introducing a crushed, solid reactant into the
housing, means for introducing a pressure sealing fluid into the
housing at a point downstream from the hopper, and outlet means for
discharging the reactant and the sealing fluid from the housing
into the reactor inlet.
8. A fluid-wall reactor according to claim 1, in which the heat
shield is made of a graphitic material.
9. A fluid-wall reactor according to claim 1, further including
reaction product cooling means disposed adjacent to the outlet end
of the reactor tube.
10. A fluid-wall reactor according to claim 1 in which the means
for attaching the first and the second support rings to the
pressure vessel includes a tubular bellows disposed within an inlet
assembly section of the pressure vessel, an inlet end of the bellow
being secured in a fluid-tight manner to the inlet assembly section
and an outlet end of the bellows being secured to the first support
ring to form a fluid-tight connection to the inlet end of the
reactor tube, the bellows being deformable to accommodate axial
expansion and contraction of the reactor tube.
11. A fluid-wall reactor according to claim 1, including means for
depositing a refractory coating upon portions of the fibrous
refractory material of the reactor tube which are disposed within
the black body cavity to increase the rigidity of the fabric.
12. A fluid-wall reactor according to claim 11, in which the
refractory coating depositing means includes sensors to determine
the pressure differential between the plenum and the reaction zone,
metering means for dispensing a refractory deposition agent into
the inert gas stream, and reactor tube outlet closure means, the
inert gas stream containing the deposition agent being directed
into the reaction zone and radially outwardly through the tube wall
into the inert fluid plenum.
13. A fluid-wall reactor according to claim 1, further including
means for enlarging the diameter of the pores in the fabric to
increase the flow of inert fluid through the tube wall.
14. A fluid-wall reactor according to claim 13, in which the means
for enlarging the diameter of the pores includes sensors to
determine the pressure differential between the plenum and the
reaction zone and metering means for dispensing an etching agent
into the inert gas stream.
15. A fluid-wall reactor according to claim 1, in which portions of
the fibrous refractory material which are heated and exposed to the
inert fluid have a coating of a refractory oxide.
16. A fluid-wall reactor according to claim 15, in which the
refractory oxide is thorium oxide, magnesium oxide, zinc oxide,
aluminum oxide, zirconium oxide or two or more mixtures
thereof.
17. A fluid-wall reactor according to claim 1, in which the
electrical means includes a plurality of electrically resistive
heating elements spaced circumferentially about the tube.
18. A fluid-wall reactor according to claim 17, in which each
electrically resistive heating element is made of a fabric of a
fibrous refractory material.
19. A fluid-wall reactor according to claim 19, in which the
fibrous refractory material is graphite or carbon.
20. A fluid-wall reactor according to claim 1, further including
means for reducing the diameter of the pores in the fabric to
decrease the flow of inert fluid through the tube wall.
21. A fluid-wall reactor according to claim 20, in which the means
for reducing the diameter of the pores includes sensors to
determine the pressure differential between the plenum and the
reaction zone and metering means for dispensing a refractory
deposition agent into the inert gas stream.
22. A fluid-wall reactor according to claim 21, in which the
refractory deposition agent is a carbonaceous gas.
23. A fluid-wall reactor according to claim 21, in which the
refractory deposition agent is a volatile metal-containing
compound.
24. A fluid-wall reactor according to claim 1, further including
means for introducing a radiant energy absorptive target into the
reactor chamber coincident with at least one point along the path
of the reactants which are transparent to radiant energy,
sufficient radiant energy being absorbed by the target to raise the
temperature of the reactants to a level required to initiate the
desired chemical reaction.
25. A fluid-wall reactor according to claim 24, in which the target
is a liquid.
26. A fluid-wall reactor according to claim 24, in which the target
is a gas which exhibits absorption in the electromagnetic spectrum
from about 100 microns to about 0.01 microns.
27. A fluid-wall reactor according to claim 24, in which the target
is finely divided carbon powder which is introduced through the
inlet end of the reactor tube along a predetermined path coincident
with the path of the reactants.
28. A fluid-wall reactor according to claim 1, in which a means for
introducing a liquid reactant into the reaction zone of the reactor
tube includes a fogging nozzle disposed within the reactor tube
adjacent an inlet of the reaction zone, the liquid reactant and an
atomizing gas being directed under pressure and mixed within the
nozzle, the liquid reactant being dispersed from the nozzle outlet
as a fog which absorbs radiant energy.
29. A fluid-wall reactor according to claim 28, in which the
fogging nozzle includes a tubular shroud secured to and disposed
radially outwardly of the nozzle, the axis of the shroud being
substantially parallel to the axis of the reactor tube.
30. A fluid-wall reactor according to claim 28, including a
plurality of fogging nozzles disposed within the reactor tube
adjacent the inlet end of the reactor zone.
31. A fluid-wall reactor according to claim 28, in which the means
for introducing a liquid reactant into the reaction zone further
includes means for introducing a sweep gas into the inlet end of
the reactor tube, the sweep gas directing the liquid reactant fog
towards the reaction zone.
32. In combination with a high temperature reactor wherein
substantially all of the heat is supplied by radiation coupling,
comprising
(1) a reactor tube having an inlet end and an outlet end, the
interior of the tube defining a reactor chamber, the reactor tube
being made of a porous refractory material capable of emitting
sufficient radiant energy to raise the temperature of reactants
within the reactor tube to a level required to initiate and sustain
the desired chemical reaction; the pores of the refractory material
being of such diameter as to permit a uniform flow of sufficient
inert fluid which is substantially transparent to radiant energy
through the tube wall to constitute a protective blanket for the
radially inward surface of the reactor tube;
(2) a fluid-tight, tubular pressure vessel enclosing the reactor
tube to define an inert fluid plenum between the reactor tube and
the pressure vessel, the inlet and outlet ends of the reactor tube
being sealed from the plenum; the pressure vessel having an inlet
for admitting the inert fluid which is directed under pressure into
the plenum and through the porous tube wall into the reactor
chamber;
(3) means for introducing at least one reactant into the reactor
chamber through the inlet end of the reactor tube, the reactants
being directed in a predetermined path axially of the reactor tube
and being confined by the protective blanket substantially
centrally within the reactor chamber and out of contact with the
inner wall of the reactor tube;
(4) electrical means disposed within the plenum and spaced radially
outwardly of the reactor tube for heating the reactor tube to the
temperature level at which it emits sufficient radiant energy to
initiate and sustain the desired chemical reaction, the radiant
energy being directed centrally therewithin substantially
coincident with at least a portion of the path of the reactants;
and
(5) a circumferential heat shield disposed within the pressure
vessel and radially outwardly of the heating means, the heat shield
reflecting radiant energy toward the reactor tube;
means for enlarging the diameter of the pores in the tube wall to
increase the flow of inert fluid through the wall.
33. A fluid-wall reactor according to claim 32, in which the means
for enlarging the diameter of the pores includes sensors to
determine the pressure differential between the plenum and the
reaction zone and metering means for dispensing an etching agent
into the inert gas stream.
34. In combination with a high temperature reactor wherein
substantially all of the heat is supplied by radiation coupling,
comprising
(1) a reactor tube having an inlet end and an outlet end, the
interior of the tube defining a reactor chamber, the reactor tube
being made of a porous refractory material capable of emitting
sufficient radiant energy to raise the temperature of reactants
within the reactor tube to a level required to initiate and sustain
the desired chemical reaction; the pores of the refractory material
being of such diameter as to permit a uniform flow of sufficient
inert fluid which is substantially transparent to radiant energy
through the tube wall to constitute a protective blanket for the
radially inward surface of the reactor tube;
(2) a fluid-tight, tubular pressure vessel enclosing the reactor
tube to define an inert fluid plenum between the reactor tube and
the pressure vessel, the inlet and outlet ends of the reactor tube
being sealed from the plenum; the pressure vessel having an inlet
for admitting the inert fluid which is directed under pressure into
the plenum and through the porous tube wall into the reactor
chamber;
(3) means for introducing at least one reactant into the reactor
chamber through the inlet end of the reactor tube, the reactants
being directed in a predetermined path axially of the reactor tube
and being confined by the protective blanket substantially
centrally within the reactor chamber and out of contact with the
inner wall of the reactor tube;
(4) electrical means disposed within the plenum and spaced radially
outwardly of the reactor tube for heating the reactor tube to the
temperature level at which it emits sufficient radiant energy to
initiate and sustain the desired chemical reaction, the radiant
energy being directed centrally therewithin substantially
coincident with at least a portion of the path of the reactants;
and
(5) a circumferential heat shield disposed within the pressure
vessel and radially outwardly of the heating means, the heat shield
reflecting radiant energy toward the reactor tube;
means for reducing the diameter of the pores in the tube wall to
decrease the flow of inert fluid through the wall.
35. A fluid-wall reactor according to claim 34, in which the means
for reducing the diameter of the pores includes sensors to
determine the pressure differential between the plenum and the
reaction zone and metering means for dispensing a refractory
deposition agent into the inert gas stream.
36. a fluid-wall reactor according to claim 35, in which the
refractory deposition agent is a carbonaceous gas.
37. A fluid-wall reactor according to claim 35, in which the
refractory deposition agent is a volatile metal-containing
compound.
Description
BACKGROUND OF THE INVENTION
The present invention relates generally to a fluid-wall reactor for
the carrying out of many high temperature chemical reactions which
previously have been regarded as impractical or only theoretically
possible. The present reactor utilizes radiation coupling as a heat
source, maintains the contemplated chemical reactions in isolation
within a protective fluid blanket or envelope out of contact with
the containing surfaces of the reactor, and provides a heat shield
which substantially encloses the radiant energy heating means and
the reaction zone to define a "black body cavity". As used herein,
the term "black body cavity" is generally intended to denote a
space which is substantially enclosed by a surface or surfaces and
from which, ideally, no radiation can escape. Within the context of
the present fluid-wall reactor, the heat shield constitutes the
enclosing surface or surfaces of the "black body cavity" and the
material from which the heat shield is fabricated (1) functions as
an insulator, inhibiting the transfer of heat from within the
"black body cavity", and (2) must be able to withstand the
temperatures generated by the radiation coupling heat source.
High temperature reactors are presently employed to carry out
pyrolysis, thermolysis, disassociation, decomposition and
combustion reactions of both organic and inorganic compounds.
Substantially all such reactors transfer heat to the reactants by
convection and/or conduction, but this characteristic inherently
produces two major problems which limit the nature and scope of the
reactions which may be carried out. Both problems result from the
fact that in a conventional reactor which transfers heat to the
reactants by convection, the highest temperature in the system is
necessarily at the interface between the inside wall of the reactor
and the reactant stream.
The first problem involves the limitations on available
temperatures of reaction which are imposed by the strength at
elevated temperatures of known reactor wall materials. The
decreasing capability of such materials to maintain their integrity
under conditions of increasing temperature is, of course, well
known. However, since it is necessary that such materials be heated
in order that thermal energy may be transferred to the reactant
stream, available reaction temperatures have been limited by the
temperature to which the reactor wall could be safely heated. This
factor is particularly critical in cases where the contemplated
reaction either must take place at or produces high pressures.
The second problem inherently results both because the wall of a
conventional reactor is at the highest temperature in the system
and because convective/conductive heat transfer requires contact
between the wall and the reactant stream. Being at such elevated
temperature, the reactor wall is an ideal if not the most desirable
reaction site in the system and, in many instances, reaction
products will accumulate and build up on the wall. Such build-up
impairs the ability of the system to transfer heat to the reactants
and this ever increasing thermal impedance requires the source
temperature to be raised progressively just to maintain the initial
rate of heat transfer into the reactant stream. Obviously, as the
build-up increases, the required source temperature will eventually
exceed the capabilities of the reactor wall material. Moreover, as
additional energy is required to sustain the reaction, the process
becomes less efficient in both the technical and economic sense.
Thus, at the point where the contemplated reaction can no longer be
sustained on the basis of either heat transfer, strength of
materials, or economic considerations, the system must be shut down
and cleaned.
Usually, cleaning is performed mechanically by scraping the reactor
wall or chemically by burning off the deposits. In some continuous
processes, it has been attempted to scrape the reactor wall while
the reaction proceeds. However, the scraping tool itself
necessarily gets hot, becomes a reaction site and, thereafter, must
be cleaned. In any event, this down time represents a substantial
economic loss. In many instances, a second system will be installed
in order to minimize lost production time. However, such additional
equipment generally represents a substantial capital investment.
Some high temperature chemical reactors include a tube which is
heated to a temperature at which its inner walls emit sufficient
radiant energy to initiate and sustain the reaction. However, as in
the case of conductive and convective reactors, for reactions
yielding solid products there is frequently an undesirable build-up
of product on the tube walls which leads to reduced heat transfer
and even clogging of the tube.
The apparatus for the manufacture of carbon black disclosed in U.S.
Pat. No. 2,062,358 includes a porous tube disposed within a heating
chamber. Hot gas is directed from a remote furnace into the
chamber, and thereafter forced through the wall of the porous tube
to mix with the reactants. Thus, only convective transfer of heat
from a fluid to reactants is employed. This, together with the
absence of a "black body cavity", necessitates the flow of a large
volume of fluid through the heating chamber in order to make up for
heat losses.
U.S. Pat. No. 2,769,772 discloses a reactor for heat-treating fluid
materials such as hydrocarbons which includes two concentric tubes
disposed in a flame heated furnace. Reactants flow axially through
the pervious inner concentric tube. A heat-carrier gas flowing in
the annular chamber between the concentric tubes is heated by
contact with the outer wall. Fluids in the inner tube are heated by
convection when the heat-carrier gas passes through the pervious
wall and mixes with them. Radiant heat transfer is expressly
avoided. In fact, it is impossible to heat the inner tube without
simultaneously heating the outer tube to at least as high a
temperature.
The surface-combustion cracking furnace of U.S. Pat. No. 2,436,282
employs the convective heat carrier gas principle similar to that
of U.S. Pat. No. 2,769,772. The furnace includes a porous,
refractory tube enclosed by a jacket. A combustible fluid from an
annular chamber is forced through the porous wall to the inside of
the tube where it is ignited. It is evident, however, that the
combustible fluid in the annular chamber will explode unless it is
forced through porous wall at a rate faster than the rate of flame
propagation back through the wall. Likewise, the temperature in the
annular chamber must be maintained below the ignition temperature
of the gas/air mixture. Combustion products from the surface flame
mix with reactants in the furnace diluting and possibly reacting
with them. Heat is imparted to the reactants by convective mixing
of the combustion products and the reactants.
U.S. Pat. Nos. 2,670,272; 2,670,275; 2,750,260; 2,915,367;
2,957,753; and 3,499,730 disclose combustion chambers for producing
pigment-grade titanium dioxide by burning titanium tetrachloride in
oxygen. In the '275 patent, which is representative of this group
of references, titanium tetrachloride is burned in a porous,
refractory tube. An inert gas is continuously diffused through the
porous tube into a combustion chamber where it forms a protective
blanket on the inner surface of tube. This gaseous blanket
substantially reduces the tendency of the titanium dioxide
particles to adhere to the walls of the reactor. Since the
combustion of titanium tetrachloride is an exothermic reaction, no
provision is made to supply heat to the reaction mixture as it
passes through tube. In fact, the '275 patent teaches that it is
advantageous to remove heat from reactor chamber either by exposing
the porous tube assembly to the atmosphere or by circulating a
cooling fluid through a coil disposed about the porous tube.
SUMMARY OF THE INVENTION
The fluid-wall reactor of the present invention transfers
substantially all of the required heat to the reactants by
radiation coupling. The reactor comprises a tube having an inlet
end and an outlet end, at least a portion of the interior of the
tube defining a reaction zone; the reactor tube is made of a fabric
of a fibrous refractory material capable of emitting sufficient
radiant energy to raise the temperature of reactants within the
reaction zone to a level required to initiate the sustain the
desired chemical reaction. The fabric has a multiplicity of pores
of such diameter as to permit a uniform flow of sufficient inert
fluid which is substantially transparent to radiant energy through
the tube wall to constitute a protective blanket for the radially
inward surface of the reactor tube. A fluid-tight, tubular pressure
vessel encloses the reactor tube to define an inert fluid plenum
between the reactor tube and the pressure vessel, the inlet and
outlet ends of the reactor tube being sealed from the plenum. The
pressure vessel has at least one inlet for admitting the inert
fluid which is directed under pressure into the plenum and through
the porous tube wall into the reaction zone. The reactor further
includes means for introducing at least one reactant into the
reaction zone through the inlet end of the reactor tube.
Thereafter, the reactants are directed in a predetermined path
axially of the reactor tube and are confined by the protective
blanket substantially centrally within the reaction zone and out of
contact with the inner wall of the reactor tube. At least one
electrical heating element is disposed within the plenum and spaced
radially outwardly of the reactor tube for heating the reactor tube
to the temperature level at which it emits sufficent radiant energy
to initiate and sustain the desired chemical reaction. The radiant
energy is directed into the reaction zone substantially coincident
with at least a portion of the path of the reactants. A heat shield
is disposed within the pressure vessel substantially enclosing the
heating elements and the reaction zone to define a black body
cavity. The heat shield reflects radiant energy inwardly toward the
reaction zone.
In contrast to the conventional convective reactors, the present
invention relies upon radiation coupling to transfer heat to the
reactant stream. The amount of heat transferred is independent both
of physical contact between the reactor wall and the stream and of
the degree of turbulent mixing in the stream. The primary
consideration for heat transfer in the present system is the
radiation absorption coefficient (.alpha.) of the reactants. The
inert fluid blanket which protects the reactor wall is desirably
substantially transparent to radiation and thus exhibits a very low
value of (.alpha.). This enables radiant energy to be transferred
through the blanket to the reactant stream with little or no energy
losses. Ideally, either the reactants themselves or a target medium
will exhibit high (.alpha.) values and will thus absorb large
amounts of energy, or alternatively, the reactants may be finely
divided (as in a fog) such that the radiation is absorbed by being
trapped between the particles. Since materials which are good
absorbers are generally good emitters of radiation, when the
reactants or targets are raised to a sufficiently high temperature,
they become secondary radiators which re-radiate energy throughout
the entire reacting volume and further enhance the heat transfer
characteristics of the system. This occurs almost instantaneously
and is subject to precise and rapid control. Moreover, the
reradiation phenomenon which ensures rapid and uniform heating of
the reactants is completely independent of the degree of turbulent
mixing which may exist in the reactant stream.
The present fluid-wall reactor for high temperature chemical
reactor process provides a solution to problems which have plagued
industry. Because heat is supplied by radiation coupling rather
than by convection and/or conduction, the temperature of the
reactant stream may be independent of both pressure vessel wall and
of the condition of the reactant stream, and the serious strength
of materials problem is overcome. Although it provides a heated
wall as a source of radiant energy, the reactor tube of the present
invention is not subjected to the high pressures which are normally
attendant to many kinds of reactions. For this reason, refractory
materials which are not suitable for use as a wall material in a
conventional reactor may be successfully employed. This feature
permits reaction temperatures far in excess of these presently
achievable and reactions which had been only theoretically feasible
may be carried out.
Carbon cloth, the preferred refractory material for the present
reactor tube, is relatively inexpensive, readily available, and may
be formed into reactor tubes substantially larger than those of
cast porous carbon presently available. Since carbon cloth is
normally flexible, any attempt to force an inert gas radially
inwardly through a reactor tube of such material would ordinarily
cause the tube to collapse. Accordingly, the present invention
contemplates the depositing of a layer of pyrolytic graphic on the
cloth to stiffen it sufficiently to withstand the pressure
differential maintained between the inert fluid plenum and the
reaction zone. Depositing a layer of pyrolytic graphite on the
cloth also permits control of the porosity of the fabric.
The provision of the protective inert fluid blanket, which is made
possible largely by the use of radiation coupling, isolates the
reactor wall from the reactor stream and makes it impossible under
normal operating conditions for any precipitates or other deposits
to accumulate and clog the system. In the event a corrosive blanket
fluid such as steam is to be used, surfaces of the reactor tube,
heating elements and heat shield which are maintained at high
temperatures and in contact with the blanket gas when the reactor
is in operation may be coated with a thin layer of refractory oxide
such as thorium oxide, magnesium oxide, or zirconium oxide. The
refractory oxide may be deposited on these surfaces by heating the
reactor to above the dissociation temperature of a volatile
metal-containing compound, introducing this compound into the
reactor chamber and allowing it to dissociate, depositing a layer
of metal on the heated surfaces. Thereafter, a gas or other
suitable material (such as molecular oxygen) may be introduced into
the reactor chamber to oxidize the metal layer, forming the desired
refractory oxide. Alternatively, the refractory coating may be
achieved in a single step if a volatile metal-containing compound
which pyrolyzes directly to an oxide is employed as a refractory
deposition agent.
The use of radiation coupling further enables the accurate and
almost instantaneous control of heat transfer rates which is
impossible to achieve in a conventional convective reactor. And,
the use of a heat shield to provide the containing surface or
surfaces of a black body cavity within which all reactions take
place, enables the achievement of unusually favorable thermal
efficiencies.
The present invention makes available for the first time on a large
scale a source of thermal energy which has never been harnessed in
this manner.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A, 1B, 1C, and 1D together constitute a composite elevation
in partial section of the reactor of the present invention; the
integral structure of the reactor has been divided along lines
A--A, B--B and C--C, respectively, in order to provide an
illustration of sufficient size to show clearly certain structural
details;
FIG. 2 is a section taken substantially along line 2--2 of FIG.
1A;
FIG. 3 is a section taken substantially along line 3--3 of FIG. 1B;
;p FIG. 4 is a section taken substantially along line 4--4 of FIG.
1B;
FIG. 5 is a section taken substantially along line 5--5 of FIG.
1C;
FIG.6 is a section taken substantially along line 6--6 of FIG.
1C;
FIG. 7 is an elevation in section of a post-reaction treatment
assembly of an alternate embodiment of the reactor of the present
invention;
FIGS. 8A and 8B together constitute a composite elevation in
partial section of an inlet assembly of an alternate embodiment of
the present invention; the integral structure of the inlet assembly
has been divided along line D--D in order to provide an
illustration of sufficient size to show clearly certain structural
details.
FIG. 9 is an elevation/schematic view of a reactor of the present
invention in combination with apparatus for pre-processing and
introducing solid reactants into an inlet assembly of the reactor
of the present invention;
FIG. 10 is a schematic representation illustrating the refractory
coating and etching systems of the reactor of the present
invention;
FIG. 11 is a schematic diagram of the temperature regulation
circuit of the reactor of the present invention;
FIG. 12 is a graphical representation of the electrical resistance
of a heating element of the reactor of the present invention as a
function of temperature and the number of layers of refractory
fabric which constitute such element; and
FIG. 13 is a schematic representation illustrating the operation of
the several control systems of the reactor of the present
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIGS. 1A through 9, inclusive, the present high
temperature chemical reactor generally comprises an inlet assembly
200 and electrode assembly 300, a main assembly 400, and a
post-reaction treatment assembly 500. The principal elements of the
present reactor include:
(A) A reactor tube 401 which has an inlet end 402 and an outlet end
403; at least a portion of the interior of the tube 401 defining a
reaction zone 404. The reactor tube 401 is made of a fabric of a
fibrous refractory material capable of emitting sufficient radiant
energy to raise the temperature of reactants within the reaction
zone 404 to a level required to initiate and sustain the desired
chemical reaction. The fabric has a multiplicity of pores of such
diameter as to permit a uniform flow of sufficient inert fluid
which is substantially transparent to radiant energy through the
tube wall to constitute a protective blanket for the radially
inward surface of the reactor tube 401. As used herein, the terms
"radiant energy" and "radiation" are intended to encompass all
forms of radiation including high-energy or impacting nuclear
particles. However, because the practical use of such radiation is
not possible under the present state of the art, black body or
other electromagnetic radiation, particularly of wavelengths
ranging from about 100 microns to 0.01 microns, is considered to be
the primary energy source upon which design considerations are to
be based. Similarly, as used herein, the term "inert fluid" is
intended to denote a gas, liquid or vapor which has a low
coefficient of absorption (.alpha.), and, as such, is substantially
transparent to radiation. Fluids which are suitable for this
purpose include simple gases such as helium, neon, argon, krypton
and xenon; complex gases which do not decompose to form a solid
product such as hydrogen, nitrogen, oxygen and ammonia; and, liquid
or gaseous water. The term "inert", as used herein, involves two
factors: the ability of the fluid to react chemically with the
material of the reactor tube 401 and the ability of the fluid to
react chemically with the materials which are being processed.
Thus, the selection of an "inert" blanket fluid depends in each
instance upon the particular environment. Except as otherwise
specifically provided, it is desirable that the fluid be inert with
respect to the reactor tube and it is usually desirable that the
fluid be inert with respect to the particular reaction being
carried out. However, it is contemplated that in some instances the
"inert"fluid of the protective blanket shall also participate in
the reaction as, for example, where iron or carbon particles are
reacted in the presence of a steam blanket to produce iron oxide
and hydrogen or carbon monoxide and hydrogen, respectively.
(B) A fluid-tight, tubular pressure vessel (which has an inlet
assembly section 201, an electrode assembly section 301, a main
assembly section 405, and a post-reaction treatment assembly
section 501) encloses the reactor tube 401 to define an inert fluid
plenum 406 between the reactor tube 401 and the pressure vessel.
The inlet and outlet ends, 402 and 403, respectively, of the
reactor tube 401 are sealed from the plenum 406. The pressure
vessel has a first inlet 408 and a second inlet 409 for admitting
the inert fluid which is directed under pressure into the plenum
406 and through the porous tube wall 401 into the reaction zone
404.
(C) Means for introducing reactants, either gaseous, liquid, or
solid, into the reaction zone 404 through the inlet end 402 of the
reactor tube 401. The reactants are directed in a predetermined
path axially of the reactor tube 401 and are confined by the
protective blanket substantially centrally within the reaction zone
404 and out of contact with the inner wall of the reactor tube
401.
(D) Electrical means including heating elements 302a, 302b, and
302c which are disposed within the plenum 406 and spaced radially
outwardly of the reactor tube 401 for heating the reactor tube to
the temperature level at which it emits sufficient radiant energy
to initiate and sustain the desired chemical reaction. The radiant
energy is directed into the reaction zone 404 substantially
coincident with at least a portion of the path of the
reactants.
(E) A heat shield 410 which is disposed within the pressure vessel
substantially enclosing the heating elements 302a, 302b, and 302c
and the reaction zone 404 to define a black body cavity. The heat
shield 410 reflects radiant energy inwardly toward the reaction
zone 404.
A. INLET ASSEMBLY
Referring particularly to FIGS. 1A and 2, the pressure vessel inlet
assembly section 201 is a tubular member having first and second
flanges, 202 and 203, at its respective ends. An annular nozzle
block 204 is secured to an annular sealing flange 205 which, in
turn, is secured in fluid-tight relationship to the first flange
202 of the inlet assembly pressure vessel section 201. A principal
atomizing gas inlet tube 206 extends through the annular nozzle
block 204 and is fixedly secured thereto by a support flange 207.
An O-ring 209 in the support flange 207 assures a fluid-tight seal
between the principal atomizing gas inlet tube 206 and the flange
207. An inlet fitting 210 is secured to an end of the principal
atomizing gas inlet tube 206 as shown in FIG. 1A. Atomizing gas
enters a plenum 211 through inlet 212.
A principal liquid reactant inlet tube 214 is disposed within the
principal atomizing gas inlet tube 206 and extends substantially
coextensively therewith. A principal liquid reactant enters the
tube 214 through inlet 215 in fitting 210.
As best shown in FIG. 1B, a fogging nozzle 216 is secured to the
outlet end of both the principal atomizing gas inlet tube 206 and
the principal liquid reactant inlet tube 214. The fogging nozzle
216 includes a tubular shroud 217 which is secured to and disposed
radially outwardly of the nozzle as shown. The axis of the shroud
217 is substantially parallel to the axis of the reactor tube 401.
In operation, the liquid reactant and the atomizing gas are
directed under pressure through tubes 214 and 206, respectively,
and, under pressure, are mixed within the nozzle 216. The liquid
reactant is thus dispersed from the nozzle outlet as a fog which
absorbs radiant energy. The shroud 217 serves to assist in
containing the liquid reactant fog centrally within a pre-reaction
zone 411 of the reactor tube 401.
As shown best in FIGS. 1A and 2, the inlet assembly of the
preferred embodiment of the present reactor may further include a
plurality of secondary inlet tubes 218a, 218b, and 218c which
enable the introduction of additional liquid reactants. The means
for introducing the secondary liquid reactant are structurally and
functionally similar to the means for introducing the principal
liquid reactant, previously described, and thus further embody
secondary atomizing gas inlet tubes 219a, 219b, and 219c and
fogging nozzles such as 220a (the additional fogging nozzles are
not shown). A representative inlet for a secondary liquid reactant
and a representative inlet for a secondary atomizing gas are
designated by reference numerals 221 and 222, respectively.
The above discussion presumes that the reactants themselves either
exhibit a relatively high radiation absorption coefficient (a) or
can be converted into a fog which absorbs radiant energy. However,
if such is not the case, a radiant energy absorptive target must be
introduced into the reactor zone 404 coincident with at least one
point along the path of the reactants. The target medium may be a
finely divided solid such as carbon powder or other suitable
material which enters the reaction zone together with the reactants
and absorbs sufficient radiant energy to raise the temperature of
the reactants to the required level. Alternatively, the target may
be a liquid such as tar, asphalt, linseed oil or diesel oil, and
may include solutions, dispersions, gels and suspensions of varied
make-up which may be readily selected from available materials to
suit particular requirements. The target may be a gas which
preferably exhibits absorption in the electromagnetic spectrum from
about 100 microns to about 0.01 microns; such gases include
ethylene, propylene, oxides of nitrogen, bromine, chlorine, iodine,
and ethyl bromide. The target may also be a solid element made of a
material such as carbon which is disposed in the reaction zone 404
along at least a portion of the path of the reactants.
Referring particularly to FIG. 1A, a sweep gas assists in directing
the liquid reactant fog toward the reaction zone 404. The sweep gas
enters nozzle block 204 through sweep gas inlet fitting 225, passes
through channel 227 and is directed axially of the reactor tube 401
toward the pre-reaction zone 411.
As shown in FIGS. 1A and 2, a reaction viewport 226 provides an
axial view into the reaction zone 404.
ELECTRODE ASSEMBLY
Referring particularly to FIGS. 1B, 3, 4 and 5, the tubular
electrode assembly pressure vessel section 310 has first and second
flange portions 303 (shown in FIG. 1A) and 304, respectively.
Electrode assembly pressure vessel section 310 is secured at its
first flange 303 to the second flange 203 of the inlet assembly
pressure vessel section 201 in fluid-tight relationship. A coolant
channel 305 is defined between the electrode assembly pressure
vessel section 301 and an electrode assembly cooling jacket 306.
Coolant enters the channel 305 through inlet 307 and exits through
outlet 308.
As shown best in FIGS. 1B and 3, copper bus bar electrodes
309a-309f are mounted on and extend through the second flange 304
of the tubular electrode assembly pressure vessel section 301.
Although there are six such electrodes 309, as a matter of
convenience only one is actually shown in detail in FIG. 1B. Each
copper bus bar electrode 309 includes a phenolic flange 310 and a
ceramic insulator 311. Each such electrode 309 is cooled by a
fluid, preferably ethylene glycol, which circulates in an internal
channel 312, entering through inlet 313 and exiting through outlet
314. An electrical connection is illustrated at 315. A
polytetrafluoroethylene seal 316 assists in preventing any leakage
from inside the inert fluid plenum 406. Although, as illustrated in
FIG. 11, the electrical system employed in connection with the
present reactor is of the 3-phase "Y" connection type, other
systems may be used where circumstances warrant.
Referring particularly to FIGS. 1B and 1C, each copper electrode
309 is secured by a tongue and groove connection to a first
extremity of a rigid carbon electrode extension 317. The electrode
extensions 317 project through but do not contact a first end
section 412 of the heat shield 410 and are secured at a second
extremity to an arcuate heating element support 318. As shown best
in FIG. 4, heating elements 302a-302c are secured at a first end to
one of the arcuate heating element supports 318 and are spaced
circumferentially about the reactor tube 401 within the inert fluid
plenum 406. The heating elements are secured at a second end to a
3-phase center connection ring 319 as shown in FIGS. 1C and 5.
Preferably, each electrically resistive heating element 302 is made
of a fabric of a fibrous refractory material such as graphite or
carbon. Heating element supports 318 and center connecting ring 319
may be made of an electrically-conductive, refractory material such
as carbon.
C. MAIN ASSEMBLY OF THE REACTOR
Referring to FIGS. 1B, 1C and 4, the tubular main assembly pressure
vessel section 405 has first and second flange portions 414 and
415, respectively. Section 405 is secured at its first flange 414
in fluid-tight relationship to the second flange 304 of the
electrode assembly pressure vessel section 301. A main assembly
coolant channel 416 is defined between the main assembly pressure
vessel section 405 and a main assembly cooling jacket 417. The
channel 416 is further defined by a spiral baffle 418. Coolant
enters the spiral channel 416 through inlet 419 and exists through
outlet 420.
The reactor tube 401 includes three zones: the prereaction zone
411, the reaction zone 404, and a post-reaction zone 422. As
previously stated, the reactor tube 401 is made of a fabric of
fibrous refractory material such as carbon or graphite. The fabric
may be knitted, woven, or non-woven. The reaction tube 401 is
secured at its outlet end 403 to a reactor tube outlet support ring
424 which, in turn, is secured in place by a reactor tube anchor
block 425. The reactor tube 401 is secured at its inlet end 402 to
a reactor tube inlet support ring 426 which, in turn, is joined in
fluid-tight relationship to a tubular bellows 427 disposed within
the pressure vessel inlet assembly section 201. An inlet end of the
bellows 427 is secured in a fluid-tight manner between the first
flange 202 of the pressure vessel inlet assembly section 201 and
the annular sealing flange 205 to insure that the inlet end of the
reactor tube 401 remains sealed from the plenum 406. The bellows
427 is deformable to accomodate axial expansion and contraction of
the reactor tube 401.
Means for applying an axial tensile force to the reactor tube 401
comprises three identical assemblies spaced equidistant about the
circumferential surface of the pressure vessel inlet assembly
section 201. For convenience, the assembly 428 which is illustrated
in FIG. 1A shall be described. Each assembly 428 includes a
translatable push rod 429 secured at one end to the reactor tube
inlet support ring 426 and at an opposite end to an annular plate
430. Each push rod 429 is supported in a bearing 431 which is
sealed in a fluid-tight manner by O-ring 432. Eye-bolt 433 which is
secured to the annular plate 430 anchors a cable 434 which extends
generally parallel to the longitudinal axis of the reactor and over
a pulley assembly 435. A weight 436 secured to an opposite end of
the cable 434 applies a force which maintains the reactor tube 401
in axial tension.
Referring particularly to FIGS. 1B and 1C, the heat shield 410
includes a first circumferential section 438 which is disposed
within the pressure vessel main assembly section 405, radially
outwardly of the heating elements 302a, 302b and 302c and between
the first end section 412 and a second end section 439 of the heat
sheild 410. As shown in FIG. 1C, the first circumferential section
438 of heat shield 410 rests in a seating ring 437 which is
preferably made of carbon. If desired, the first circumferential
portion of the heat shield 410 may be extended in a direction
toward the electrode assembly 300 to include a second
circumferential portion 440 as shown in FIG. 1B.
In that the heat shield 410 reflects rather than transfers heat, it
functions as an insulator and may thus be made of any material
which exhibits this characteristic and which can withstand the
temperatures generated by the heating elements 302a, 302b and 302c.
Although molybdenum has been found to be a satisfactory material
for a heat shield of a type required in the present high
temperature chemical reactor, it is preferred that the heat shield
410 be made of a graphitic material such as pyrolytic graphite or a
material manufactured by Union Carbide Corporation and sold under
the tradename "Grafoil".
Radiometer viewports 441 and 442 are provided in the main assembly
section 400. Viewport 442 enables observation and measurement of
the temperature of the reaction zone 404 of the reactor tube 401
and viewport 441 enables observation and measurement of the
temperature of heating element 302c.
D. POST-REACTION TREATMENT ASSEMBLY
As shown in FIG. 1C, a first flange portion 502 of the
post-reaction treatment assembly pressure vessel section 501 is
secured in a fluid-tight manner to a fluid-cooled interface flange
503 which, in turn, is secured in a fluid-tight manner to the
second pressure vessel main assembly section flange 415. A coolant
channel 504 is defined between post-reaction treatment assembly
cooling jacket 505 and the post-reaction treatment assembly
pressure vessel section 501. Coolant flows into the channel 504
through inlet 506 and exits through outlet 507. Radiometer viewport
509 is provided to enable observation and temperature measurement
within the post-reaction zone 422 of the reactor tube 401.
Reaction products exiting the outlet end 403 of the reactor tube
401 of the embodiment of FIG. 1 pass into a first section 510 of
heat sink 511. As shown in FIGS. 1C and 1D, the first section 510
of the heat sink 511 includes an inner tubular wall 512 and an
outer tubular wall 513 which define therebetween a coolant channel
514. Spiral coolant baffle 515 directs the coolant which enters
through inlet 516 and exits through outlet 517. A first
thermocouple probe 518 which extends into the first section 510 of
the heat sink 511 enables the measurement of temperature of the
entering reaction products. A second thermocouple probe 519 which
extends into the first section 510 of the heat sink 511 measures
the temperature of the reaction products about to exit.
Referring particularly to FIG. 1D, the first section 510 of the
heat sink 511 is joined to a second section 520 by flanges 521 and
522, respectively. The second section 520 includes an inner wall
524 and an outer wall 525 which define therebetween a coolant
channel 526. Coolant enters the channel 526 through inlet 527 and
exits through outlet 528. Thermocouple probes 530 and 531 enable
measurement of the temperature of reaction products entering the
second section 520 and exiting the second section 520,
respectively.
In the embodiment of FIG. 7, a post-reaction treatment assembly
500a includes a post-reaction treatment assembly pressure vessel
section 501a having a flange portion 502a which is secured in a
fluid-tight manner to a fluid-cooled, interface flange such as
flange 503 illustrated in FIG. 1C. A coolant channel 504a is
defined between a post-reaction treatment assembly cooling jacket
505a and the post-reaction treatment assembly pressure vessel
section 501a. Coolant flows into the channel 504a through inlet
506a and exits through outlet 507a. Radiometer viewport 509a
enables observation and temperature measurement in the
post-reaction zone 422 of the reactor tube 401.
Reaction products exiting the outlet end 403 of the reactor tube
401 of the embodiment of FIG. 7 at high temperature pass into a
variable profile, counter-flow heat exchanger 532 which abuts the
reactor outlet 403 at its inlet end 533. The heat exchanger 532
includes an inner tubular wall of refractory material 534, an outer
tubular wall of refractory material 535 spaced concentrically
outwardly from the inner wall 534, and a spiral baffle of
refractory material 536 disposed between the walls 534 and 535 to
define a spiral, annular coolant channel 537. The inner tubular
wall 534, outer tubular wall 535 and spiral baffle 536 together
constitute a high temperature spiral heat exchanger assembly 544
which rests on a resilient carbon felt cushion 545 disposed on end
plate 546 of heat exchanger pressure vessel section 547. Coolant
inlets 538, 539 and 540 extend through the outer tubular wall 535
in communication with the spiral coolant channel 537.
In the specific embodiment illustrated in FIG. 7, after circulating
throughout the spiral coolant channel 537 in a pre-selectable,
variable, and controllable manner, the coolant is discharged at an
outlet 541 of the spiral annular channel 537 adjacent the inlet end
533 of the heat exchanger 532. Thereafter, the coolant circulates
through inlet port 542 in reactor tube anchor block 425a into the
inert fluid plenum 406. In such case, it is apparent that the
coolant employed should be a fluid which is the same as or, at
least, compatible with the inert fluid which is present in the
plenum 406. However, since the operation of the heat exchanger 532
does not require that the coolant be circulated into the plenum
406, alternative circulation patterns and expedients are feasible.
In such instances, the choice of coolant fluid is not limited by
the criteria set forth above. Circumferential heat exchanger
cooling jacket 548 is spaced radially outwardly of the heat
exchanger pressure vessel section 547, defining therebetween an
annular channel 549. Coolant is introduced into channel 549 through
inlet 550 and exits through outlet 551.
E. INLET ASSEMBLY FOR SOLID REACTANTS
Inlet assembly 200a of the embodiment of FIGS. 8A and 8B is
substantially identical to the inlet assembly 200 of FIGS. 1A and
1B except that means for introducing a principal solid reactant of
inlet assembly 200a replaces the means for introducing a principal
liquid reactant of inlet assembly 200. For convenience, only the
features of the embodiment of FIGS. 8A and 8B which differ from
corresponding features of the embodiment of FIGS. 1A and 1B shall
be described.
A solid reactant inlet tube 232 extends through the annular nozzle
block 204 and is fixedly secured thereto by a support flange 235. A
principal solid reactant, preferably finely divided, enters inlet
tube 231 through inlet 233 in support flange 235 and exits within
reactor tube 401 adjacent the prereaction zone 411. Secured to and
disposed radially outwardly of outlet 234 is a tubular shroud 217,
the axis of which is substantially parallel to the axis of the
reactor tube 401. Shroud 217 assists in containing finely divided
solid reactants centrally within the prereaction zone 411 of
reactor tube 401.
Referring to FIG. 9, a solid reactant feed system 238 is shown in
combination with a high-temperature reactor having an inlet
assembly 200a of the type depicted in FIGS. 8A and 8B. A supply bin
240 for holding the solid reactant feeds a crusher 241, which, in
turn, feeds a sieve 242. Coarse product output 245 of the sieve 242
is recycled to the crusher 241 and fine product output 243 is fed
to a hopper 244 which is secured to an elongated tubular housing
246. Helical feed screw 247 is rotatably mounted within the housing
246 and is driven by motor 248. A pressure-sealing fluid may be
introduced into the housing 246 through an inlet nozzle 249 located
at a point downstream from the hopper 244; the interior of reactor
tube 401 is thus sealed from the atmosphere. The solid reactant and
the sealing fluid are discharged from housing 246 into the reactor
through an outlet 250.
F. REFRACTORY COATING AND ETCHING SYSTEMS
For reasons set forth below, it is contemplated that a refractory
coating may be deposited on surfaces of reactor tube 401, heating
elements 302, and heat shield 410 which are exposed to the blanket
gas and to high temperatures during operation of the reactor. Such
refractory coating may be, for example, pyrolytic carbon or a
refractory oxide such as thorium oxide, magnesium oxide, zinc
oxide, aluminum oxide, or zirconium oxide. It is further
contemplated that portions of the surface of the reactor tube 401
may be selectively etched or eroded.
Referring to FIG. 10, a refractory coating and etching system 600
is schematically represented and comprises a first refractory
deposition agent metering system 601 having a carbonaceous gas
supply 602 connected to a carbonaceous gas metering line 603. The
metering line 603 has an on/off valve 604 connected to a needle
valve 605 and a flow meter 606. A first feeder line 608 connects
the carbonaceous gas metering line 603 to an admixture gas supply
line 607.
A second refractory deposition agent metering system 610 includes a
carrier gas supply 611 connected to a carrier gas metering line 612
which has an on/off valve 613, a needle valve 614, and a flow meter
615. The carrier gas metering line 612 is connected to a bubble
tube 616 disposed within a tank 617 which contains a solution of a
volatile metal-containing compound. The temperature of the tank 617
is regulated by a temperature controller 618 which senses the
temperature of the tank by a thermocouple 619 and supplies heat to
the tank, as required, by an electric heating mantle 620. An outlet
end 621 of bubble tube 616 is submerged in the solution contained
in the tank 617. An outlet 622 of the tank 617 connects a second
feeder line 623 to the tank 617 at a point above the solution
surface. The second feeder line 623 is also connected to the
admixture gas supply line 607.
In an etching agent metering system 625, an etching agent supply
626 is connected to an etching agent metering line 627 which
includes, in series, an on/off valve 628, a needle valve 629, and a
flow meter 630. Connected to the etching agent metering line 627 is
a third feeder line 631, which is connected to the admixture gas
supply line 607.
The three lines 608, 623, and 631, all feed into the admixture gas
supply line 607, which branches at a T-joint 632. A first branch
line 633 includes a first branch line valve 634 and is connected to
a first inlet of an inert fluid mixing manifold 635. A second
branch line 636 includes a second branch line valve 637 and is
connected to a first inlet of a sweep gas mixing manifold 638.
An inert fluid supply 640 is connected to an inert fluid metering
line 641 which includes an on/off valve 642, a needle valve 643 and
a flow meter 644 which is connected to a second inlet of inert
fluid mixing manifold 635. An outlet of mixing manifold 635 is
connected to an inert fluid supply line 645 which, in turn, is
connected to the pressure vessel inlets 408 and 409 for directing
the inert fluid into the inert fluid plenum 406. A plenum pressure
sensor 646 is connected to the inert fluid supply line 645 and is
in communication with the plenum 406 for measuring the pressure of
the inert fluid within the plenum. A plenum exhaust valve 647 is
also connected to the inert fluid supply line 645 and provides an
outlet for discharging fluid from the plenum.
A sweep gas supply 648 is connected to a metering line 649 which
includes an on/off supply valve 650, a needle valve 651, and a flow
meter 652 which is connected to a second inlet of the sweep gas
mixing manifold 638. An outlet of mixing manifold 638 is connected
to a sweep gas supply line 653 which, in turn, is connected to the
sweep gas inlet fitting 225 for introducing the sweep gas into the
interior of the reaction tube 401. A reaction zone pressure sensor
654 which connects to the sweep gas supply line 653 and which
communicates with the interior of the reactor tube 401, measures
the pressure in the reaction zone of the reactor.
As best shown in FIG. 1D, a reactor tube outlet closure valve 655
is secured to the second section 520 of the heat sink 511 by
flanges 555 and 656.
When the reactor is in operation, a pressure differential must be
maintained between the inert fluid in plenum 406 and gas in the
reactor tube 401 to cause a uniform flow of inert fluid radially
inward through the porous wall of the tube 401. It is thus
advantageous that the fabric of tube 401 be sufficiently stiff that
the pressure differential may be maintained without inward collapse
of the tube 401. Accordingly, it is contemplated that a refractory
coating such as pyrolytic carbon be deposited upon portions of the
fibrous refractory material of the reactor tube 401 which are
disposed within the black body cavity to increase the stiffness or
dimensional stability of the fabric.
To deposit such coating, reactor tube outlet closure valve 655 is
closed and the reactor tube 401 is heated to about 3450.degree. F.
Next, the on/off valve 650 in the sweep gas metering line 649 is
opened, the on/off valve 642 in the inert fluid metering line 641
is closed, and the plenum exhaust valve 647 is opened, permitting
sweep gas to flow into the interior of the reactor tube 401, then
radially outwardly through the porous wall of the tube 401 into the
plenum 406, and, finally through the pressure vessel inlets 408 and
409 and the plenum exhaust valve 647. This tends to expand the tube
401 to its maximum diameter. Thereafter, the on/off valve 604 in
the carbonaceous gas metering line 603 is opened. The needle valves
605 and 651 are adjusted to set the flow rates of the carbonaceous
gas and the sweep gas, respectively, to suitable values as
registered on flow meters 606 and 652. The first branch line valve
634 is closed and the second branch line valve 637 is opened so
that the carbonaceous gas flows through the first feeder line 608,
the admixture gas supply line 607, the T-joint 632, the second
branch line 636, and into the sweep gas mixing manifold 638 where
it mixes with the sweep gas and flows into the interior of the
reactor tube 401 through sweep gas supply line 653 and sweep gas
inlet fitting 225.
The carbonaceous gas dissociates on the heated surfaces which it
contacts, depositing a pyrolytic graphite coating. Thus, pyrolytic
graphite is generally deposited on the portions of the reactor tube
401, the heating elements 302, and the heat shield 410 which are
within the black body cavity.
Since the portion of the reactor tube 401 which lies within the
pre-reaction zone 411 is outside of the black body cavity and,
thus, may not be heated conveniently to temperatures above the
decomposition temperature of the carbonaceous gas, it is
contemplated that a stainless steel screen 450, shown in FIGS. 1A
and 1B, be provided to prevent the flexible reactor tube 401 from
collapsing inwardly under the pressure differential of the inert
fluid, although it has been found that increased tension on the
porous fabric accomplishes substantially the same result.
To control the rate of flow of inert fluid through the walls of the
reactor tube 401, the diameter of the pores in the tube wall may be
reduced or enlarged while the reactor is in operation by mixing a
refractory deposition agent or an etching agent with the inert
fluid. The pressure differential between the plenum and the
reaction zone may be monitored by the pressure sensors 646 and 654
and the rate of flow of inert fluid through the wall may be
monitored by the flow meter 644.
When the pressure differential becomes too low for the desired rate
of flow of inert blanket gas, the diameter of the pores in the tube
of the reactor wall may be reduced by opening the on/off valve 604
and adjusting the needle valve 605 to allow a carbonaceous gas from
the carbonaceous gas supply 602 to flow through carbonaceous gas
metering line 603. The second branch line valve 637 is closed and
the first branch line valve 634 is opened to direct the
carbonaceous gas into the inert fluid mixing manifold 635 and
thence into the plenum 406 through the inert fluid supply line 645
and the pressure vessel inlets 408 and 409. The plenum exhaust
valve 647 remains closed and the reactor tube outlet closure valve
655 remains open during normal operation of the reactor. The
carbonaceous gas dissociates on the heated surfaces within the
reactor which it contacts. Accordingly, carbonaceous gas which
flows into the pores of the fabric of the wall of reactor tube 401
dissociates, depositing a coating of pyrolytic graphite which
reduces pore diameter. Since the pressure differential across the
reactor tube wall will increase for a fixed flow of inert fluid,
the decrease in porosity of the tube may be monitored with pressure
sensors 654 and 646 and flow meter 644 as the graphite is
deposited. When the pressure differential exceeds a predetermined
value, the growth of the graphite coating may be halted by closing
the on/off valve 604 in the carbonaceous gas metering line 603. The
entire process of reducing the diameter of the pores in the reactor
tube wall may be carried out without interrupting the operation of
the reactor.
Conversely, it may be necessary to increase the diameter of the
pores of the reactor tube 401. In this case, an etching agent such
as steam or molecular oxygen from the etching agent supply 626 is
mixed with the inert fluid by opening valve 628, adjusting needle
valve 629 in the etching agent metering line 627, closing the
second branch line valve 637, and opening the first branch line
valve 634. The etching agent mixes with the inert fluid in inert
fluid mixing manifold 635 and flows into the plenum 406 through the
pressure vessel inlets 408 and 409. The etching agent attacks
heated surfaces which it contacts, thereby increasing the diameter
of the pores of the heated portion of the reactor tube 401. The
flow of etching agent may be continued until pressure sensors 654
and 646 indicate a sufficiently low pressure differential across
the reactor tube 401 for the desired rate of flow of inert fluid as
monitored by flow meter 644. As with reducing the pore diameter
with the carbonaceous gas, this process may be carried out while
the reactor is in operation.
It may be advantageous in some applications to use steam or another
medium which reacts chemically with the materials being processed
as the inert fluid. To prevent or, at least, to retard the
corrosion of materials of which the reactor is constructed, it is
contemplated that a coating of a refractory oxide such as thorium
oxide, magnesium oxide, zinc oxide, aluminum oxide, or zirconium
oxide be deposited on the portions of the reactor tube 401, heating
elements 302, and heat shield 410 which come into contact with the
inert fluid and operate at high temperatures. To deposit a coating
of refractory oxide, a refractory deposition agent which is a
volatile metal-containing compound such as methylmagnesium
chloride, magnesium ethoxide, or zirconium-n-amyloxide may be
employed. Methylmagnesium chloride, for example, decomposes on a
surface heated to about 1100.degree. F. to deposit a coating of
magnesium metal. The hot magnesium metal is subsequently oxidized
by introducing steam or molecular oxygen into the plenum 406.
Zirconium-n-amyloxide and magnesium ethoxide both generally
decompose on heated surfaces to form zirconium oxide or magnesium
oxide respectively.
Referring to FIG. 10, the volatile metal-containing compound may be
introduced into the plenum 406 by causing a carrier gas from the
supply 611 to flow through the metering line 612 by opening the
on/off valve 613. The needle valve 614, adjusts carrier gas flow
rate to a suitable value as measured by flow meter 615. The tank
617 contains, for example, a solution of the volatile metal
containing compound such as methylmagnesium chloride dissolved in
diethyl ether or zirconium-n-amyloxide dissolved in
tetrahydrofuran. The carrier gas flows through the bubble tube 616
and into the solution of tank 617. The second branch line valve 637
remains closed and the first branch line valve 634 remains open in
order that the carrier gas, solvent vapor, and metal-containing
compound vapor are directed sequentially through the outlet 622 of
the tank 617, the second feeder line 623, the admixture gas supply
line 607, and the first branch line 633, and into the inert fluid
mixing manifold 635 where they are mixed with the inert fluid and
then carried to the plenum 406 over the inert fluid supply line 645
and through the pressure vessel inlets 408 and 409. The volatile,
metal-containing compound decomposes on hot surfaces which it
contacts within the reactor. If it decomposes into a pure metal,
oxygen or steam are subsequently introduced into the plenum 406 to
cause formation of the oxide.
G. PROCESS VARIABLE CONTROL SYSTEMS
FIG. 11 illustrates a reactor temperature control system 700.
There, heating elements 302a, 302b and 302c are depicted in
schematic form connected in a "Y" configuration circuit, one end of
each heating element being connected to a tie point 701 and the
other end being connected to a branch 702a, 702b, or 702c of a
three-phase power line 702. The tie point 701 corresponds to the
three-phase connecting ring 319 of FIG. 1C. The power line 702
connects to a heater power output 703 of a power controller 704,
which, in turn, connects to a principal three-phase power line 705
and a firing circuit 706. The principal three-phase power line 705
supplies current, preferably at 540 volts, for heating the reactor.
A radiometer 708 disposed within the viewport 441 of FIG. 1B is
focussed on the heating element 302c and produces a signal,
generally in the millivolt range, which corresponds to the
temperature of the heating element. An "MV/I" converter 709
amplifies the radiometer signal and converts it to an electric
current. A setpoint controller 707, an output signal line 712 for
connection to a computer (not shown), and a recorder 710 which
makes a permanent log of the temperature measured by the radiometer
708 are all connected to the converter 709. An input signal line
713 connects a control signal input 711 of the setpoint controller
707 a computer (not shown). Current meters 750a, 750b, and 750c are
inserted in the three branches 702a, 702b, and 702 c respectively,
to measure the current supplied to heating elements 302a-c; and,
voltmeters 751a, 751b, and 751c are tied to the branches 702a-c to
measure the voltages across the heating elements. The power
dissipated in the heating elements and the electrical resistance of
the heating elements can be calculated from such voltage and
current measurements. Knowledge of the electrical resistance of
each heating element provides information as to its physical
integrity since, as a heating element erodes, its electrical
resistance increases.
FIG. 12 is a graph of the electrical sheet resistance of a sample
of graphite cloth (sold under the trade name of "WCA Graphite
Cloth" by Union Carbide Corporation) as a function of the
temperature of the cloth. The cloth has been stiffened with
pyrolytic graphite by heating and exposing it to an atmosphere of a
carbonaceous gas, generally according to the procedure described
above. The vertical axis of the FIG. 12 graph gives the sheet
resistance in units of "ohms per square" since, as is known, the
resistance measured between opposing edges of squares of a
resistive material of a given thickness is independent of the
dimensions of the square. Thus, the resistance at a particular
temperature of a heating element formed from a single rectangular
strip of "WCA Graphite Cloth" may be found by considering the strip
to be made up of squares of the cloth connected in series. For
example, the resistance of a strip 6 inches by 51 inches at
2500.degree. F. measured between the two six-inch sides is found by
multiplying (51/6) times 0.123 ohms, the sheet resistance at
2500.degree. F. given on FIG. 12. The resistance of a heating
element made up of more than one layer of fabric, each layer having
the same dimensions and therefore the same resistance, is found by
dividing the resistance of a single layer by the number of layers.
For convenience, the calculated sheet resistances in "ohms per
square" for samples of stiffened "WCA Graphite Cloth" made up of 2,
3, and 4 layers have also been graphed on FIG. 12.
In operation, after the setpoint controller 707 is set to a
specified temperature either manually or by a computer, it compares
such temperature with the measured temperature of the electrode
302c and produces an error signal which depends upon the algebraic
difference between the measured temperature and the specified
temperature. The setpoint controller 707 controls the firing
circuit 706, which, in response to the error signal, causes the
power controller 704 to increase or decrease the power supplied to
the heating elements to reduce, as necessary, the magnitude of the
error signal, causing the temperature of the heating element 302c
to approach the specified temperature. Because the heating element
302c is within the black body cavity enclosed by the heat shield
410, its temperature is generally representative of the temperature
of surfaces throughout the cavity. However, radiometers focussed on
other surfaces within the black body cavity may also be used for
temperature control.
As shown in FIG. 13, process variables in addition to temperature
may be regulated by feedback control systems as, for example, a
principal liquid reactant feed rate regulation system 714 which
includes a supply 715 communicating with a metering system 716 over
a feed line 717. The metering system 716 controls the flow rate of
the principal reactant and may include, for example, a variable
speed pump and pump controller or a variable orifice valve and
valve controller. An output 718 of the principal reactant metering
system 716 is connected to a flow rate transducer 719 which
produces an electrical signal output 720 corresponding to the rate
of flow of the principal reactant. An output 721 of the principal
reactant flow rate transducer 719 is connected to the principal
liquid reactant inlet pipe 215. A signal output 722 of the reaction
zone pressure sensor 654 and the signal output 720 of the flow rate
transducer 719 are connected to the first and second signal inputs,
respectively, of the principal reactant metering system 716. An
output of a computer system 723 is connected to a third input of
the metering system 716.
In one mode of operation of the principal liquid reactant feet rate
regulation system 714, the computer system 723 communicates both a
pre-selected value for the principal reactant flow rate and an
upper limit for the reaction zone pressure to the principal
reactant metering system 716 which compares the pre-selected flow
rate with that measured by the transducer 719 and adjusts the flow
rate of approach the selected value, provided, however, that the
reaction zone pressure is below the prescribed upper limit. Should
the reaction zone pressure exceed this upper limit, the metering
system 716 will lower the pressure by reducing the flow rate of the
principal reactant.
A secondary liquid reactant flow rate regulation system 724 is
another feedback control system which includes a supply 725
communicating with a metering system 726 over a feed line 727. The
secondary reactant metering system 726 may be of the same type as
the principal reactant metering system 716. An output 728 of the
secondary reactant metering system 726 is connected to a flow rate
transducer 729 which produces a signal corresponding to the rate of
flow of the secondary reactant. An output 731 of the transducer 729
is connected to the secondary reactant inlet 221. A signal output
722 of the reaction zone pressure sensor 654 and a signal output
730 of the secondary reactant flow rate transducer 729 are
connected to separate signal inputs of the secondary reactant
metering system 726, and an output of the computer system 723 is
connected to a third input. The secondary liquid reactant flow rate
regulation system 724 may be operated in a mode analagous to that
described above for the principal liquid reactant regulation system
714.
In an inert fluid flow rate regulation system 734, an output of the
inert fluid supply 640 is connected to the needle valve 643, which,
in turn, is connected to the on/off valve 642. Valve 642 is
connected to an inert fluid flow rate transducer 735. A signal
output 736 of the transducer 735 is connected to a first input of
an inert fluid needle valve controller 737. A second input of the
needle valve controller 737 is connected to the computer system 723
and a third input is connected to the plenum pressure sensor 646.
The opening of the needle valve 648 may be set by the controller
737. An inert fluid output of transducer 735 is connected to the
pressure vessel inlets 408 and 409 of the reactor. For convenience,
the plenum exhaust valve 647, flow meter 644 and inert fluid mixing
manifold 535, of FIG. 10 are not shown in FIG. 13, and the inert
fluid flow rate transducer 735 of FIG. 13 is not shown in FIG.
10.
In operation, the on/off valve 642 is opened, allowing the inert
fluid to flow through transducer 735 and into the inlets 408 and
409. The needle valve controller 737 compares a flow-rate signal
from the transducer 735, to a flow rate specified by the computer
system 723 and adjusts needle valve 643 accordingly, provided,
however, that the plenum pressure as sensed by pressure senso 646
does not exceed an upper limit also specified the by computer
system 723. If the pressure is excessive, the needle valve
controller 737 reduces the flow rate to lower the pressure.
A reactor temperature control system 700, shown in detail in FIG.
11 and depicted schematically in FIG. 13, comprises a reactor
temperature controller 738 which includes the power controller 704,
firing circuit 706, set point controller 707, converter 709,
recorder 710, and meters 750 and 751 shown in FIG. 11. The
radiometer 708 (not shown in FIG. 13) is housed within the viewport
441 and connected to the controller 738. The three-phase power line
702 connects the heater power output 703 of the reactor temperature
controller 738 to the heating elements 302 (not shown in FIG. 13)
through the electrodes 309. Thus, the level of electrical power
supplied at the heater power output 703 determines the temperature
of the reactor tube 401. The control signal input 711 and an output
of the reactor temperature controller 738 are connected to the
computer system 723 by the inut signal line 713 and the output
signal line 712, respectively.
A reactor product sampler 740, connected to an outlet 741 located
adjacent the reactor outlet closure valve 655, transfers at
preselected time intervals samples of reaction product into a
sample inlet 742 of a gas chromatograph 743. An electrical signal
at an output 744 of the chromatograph 743 responds to changes in
the chemical composition of the samples. For example, the gas
chromatograph 743 in conjunction with the reaction product sampler
740 may produce a signal which corresponds to the concentration of
ethylene in a process for the partial pyrolysis of a
hydrocarbon.
Outputs of the gas chromatograph 743 are connected to a recorder
749 and the computer system 723. An input 745 of the computer
system 723 is connected to transducers for the process variables by
a data bus 746, which includes signal lines connected to the flow
rate transducers 719, 729 and 735, pressure sensors 646 and 654,
temperature controller 738, and gas chromatograph 743. Other
transducers may be tied to the data bus 746 as desired. An output
747 of the computer system 723 is connected to a command bus 748
which includes signal lines tied to the principal reactant metering
system 716, secondary reactant metering system 726, reactor
temperature controller 738, and inert fluid needle valve control
737. The computer system 723 may include a digital computer, an
analog-to-digital converter for converting analog signals of the
transducers to digital data for the computer, a digital-to-analog
converter for converting digital signals from the computer to
analog control signals, and a multiplexer for switching among
signal lines in the data bus 746 and the command bus 748.
It is contemplated that during a process run the computer system
723 may specify and monitor process variables by signals
communicated over the command bus 748 and the data bus 746. Thus,
the computer system 723 may supervise the operation of the reactor
to ensure that process variables remain within specified ranges.
Moreover, the computer may be programmed to search for optimum
operating conditions for a particular process by making systematic
variations in the process variables while monitoring the output of
the reactor with the chromatograph 743. For example, the computer
may be programmed to search for reactor temperatures and feedstock
flow rates which maximize the ethylene concentration in the output
for a particular hydrocarbon feedstock. The computer system 723 may
also be incorporated in feedback control systems; such as a
reaction product control system which includes in addition to the
computer system 723 the reaction product sampler 740, the gas
chromatograph 743, the reactor temperature controller 738, and the
three-phase power line 702 connected to the heating elements 302.
In this reaction product control system, the computer system
compares the chemical composition of samples of reaction product
withdrawn from the reactor to a preselected composition and
generates an electrical signal at its output 747 corresponding to
deviations in the chemical composition of the samples. The output
747 of the computer system 723 is connected to the input 711 of the
reactor temperature controller to enable variation of the
temperature of the reactor tube in response to changes in the
signal from the computer system, reducing the deviations in the
chemical composition of the reaction products. Other process
variables such as the feedrates of selected reactants and the
pressure in the reaction zone may also be controlled by similar
feedback control systems.
UTILIZATION OF THE FLUID-WALL REACTOR
The fluid-wall reactor of the invention may be used in virtually
any high temperature chemical reaction, many of which reactions
have been previously regarded as either impractical or only
theoretically possible. Utilizing this fluid-wall reactor, such
high temperature chemical reaction processes can be conducted at
temperatures up to about 6000.degree. F. by (1) generating within
the interior of the porous reactor tube an annular envelope
consituting an inert fluid which is substantially transparent to
radiant energy to form a protective blanket for the radially inward
surface of the reactor tube, the annular envelope having
substantial axial length and the interior of the envelope defining
a reaction chamber; (2) passing at least one reactant (which may be
either in solid, liquid or gaseous state) through the reaction
chamber along a predtermined path substantially coincident with the
longitudinal axis of the envelope, the reactants being confined
within the reaction chamber; and (3) directing high intensity
radiant energy into the reaction chamber to coincide with at least
a portion of the predetermined path of the reactants, sufficient
radiant energy being absorbed within the reaction chamber to raise
the temperature of the reactants to a level required to initiate
and sustain the desired chemical reaction.
Among the reactions which may be carried out in the fluid-wall
reactor of the invention are the dissociation of hydrocarbons and
hydrocarbonaceous materials, such as coal and various petroleum
fractions, into hydrogen and carbon black; the steam reforming of
coal, petroleum fractions, oil shale, tar sands, lignite, and any
carbonaceous or hydrocarbonaceous feedstock into synthesis gas
mixtures; the partial dissociation of hydrocarbons and
hydrocarbonaceous materials into lower molecular weight compounds;
the partial pyrolysis of saturated hydrocarbons into unsaturated
hydrocarbons, such as ethylene, propylene and acetylene; the
conversion of organic waste materials, such as sewage sludge, into
a fuel gas, the complete or partial desulfurization of
sulfur-containing hydrocarbonaceous feedstocks; and the reduction
of mineral ores with hydrogen, carbon, synthesis gas, or other
reducing agent.
* * * * *